1. Field of the Art
This invention relates generally to a medical puncture instrument, and more particularly to a puncture instrument for punctured high frequency treatments, having a high frequency electrode on a puncture needle member to be driven into a target organ or tissues in an intracorporeal region of a patient for a high frequency treatment.
2. Description of the Prior Art
For instance, ultrasound endoscopes are widely resorted to in the medical fields not only for intracorporeal examinations and diagnosis but also for therapeutic purposes to give an appropriate treatment to a diseased portion on the basis of the results of an examination or diagnostic observation. In many cases, the ultrasound endoscopes of this sort are provided with an ultrasound imaging means along with an endoscopic observation means at the fore end of a catheter-like insert portion to be introduced into an intracavitary portion of a patient. The endoscopic observation means is suitable for examinations of conditions of intracavitary walls, while the ultrasound observation means is suitable for examinations of tissues in deeper intracorporeal regions. In case a diseased portion is spotted by any of these examinations, there arises a necessity for inserting a therapeutic instrument for the treatment of the diseased portion. For this purpose, the ultrasound endoscopes are usually provided with the so-called biopsy channel which is designed to guide a bioptic or therapeutic instrument to be inserted into a particular intracorporeal portion under observation through the endoscopic or ultrasound imaging means. Some bioptic or therapeutic instruments are inserted into and manipulated through a biopsy channel on an endoscope for the treatment of a certain intracorporeal portion, as in the case of forceps and high frequency therapeutic instruments which are used for sampling intracavitary wall tissues or for coagulation or hemorrhage control treatments. On the other hand, it has been known in the art to penetrate a puncture instrument into an intracorporeal organ or tissues of interest through an intracavitary wall for injection of a medicinal liquid or for an aspiratory or suctional drainage treatment.
In this connection, conventional instruments designed for high frequency therapeutic treatments within an intracavitary tract, for example, are unable to treat cancer cells or other diseased portions which exist underneath the mucous membrane. On the other hand, conventional puncture needles are designed to serve for a treatment of a specific nature such as injection of a medicinal liquid or suctional evacuation of a diseased portion, and thus have only a limited range of application, precluding applications to other treatments like high frequency treatments.